bool TryGetLastSuccessfulRead(ServiceContext context, out TimeoutManagerDataEntity lastSuccessfulReadEntity)
{
var query = from m in context.TimeoutManagerData
where m.PartitionKey == GetUniqueEndpointName()
select m;
lastSuccessfulReadEntity = query
.AsTableServiceQuery(context)
.AsEnumerable() //TSQ does only follows continuation tokens for listings, not for single entity results, yet continuation tokes can still happen in this case
.SafeFirstOrDefault();
return(lastSuccessfulReadEntity != null);
}
private bool TryGetLastSuccessfullRead(ServiceContext context, out TimeoutManagerDataEntity lastSuccessfullReadEntity)
{
try
{
lastSuccessfullReadEntity = (from m in context.TimeoutManagerData
where m.PartitionKey == GetUniqueEndpointName()
select m).FirstOrDefault();
}
catch
{
lastSuccessfullReadEntity = null;
}
return(lastSuccessfullReadEntity != null);
}
private void UpdateSuccesfullRead(ServiceContext context, TimeoutManagerDataEntity read)
{
try
{
if (read == null)
{
read = new TimeoutManagerDataEntity(GetUniqueEndpointName(), string.Empty)
{
LastSuccessfullRead = DateTime.UtcNow
};
context.AddObject(ServiceContext.TimeoutManagerDataTableName, read);
}
else
{
context.Detach(read);
context.AttachTo(ServiceContext.TimeoutManagerDataTableName, read, "*");
context.UpdateObject(read);
}
context.SaveChangesWithRetries(SaveChangesOptions.ReplaceOnUpdate);
}
catch (DataServiceRequestException ex) // handle concurrency issues
{
var response = ex.Response.FirstOrDefault();
//Concurrency Exception - PreCondition Failed or Entity Already Exists
if (response != null && (response.StatusCode == 412 || response.StatusCode == 409))
{
return;
// I assume we can ignore this condition?
// Time between read and update is very small, meaning that another instance has sent
// the timeout messages that this node intended to send and if not we will resend
// anything after the other node's last read value anyway on next request.
}
throw;
}
}
void UpdateSuccessfulRead(ServiceContext context, TimeoutManagerDataEntity read)
{
try
{
if (read == null)
{
read = new TimeoutManagerDataEntity(GetUniqueEndpointName(), string.Empty)
{
LastSuccessfullRead = DateTime.UtcNow
};
context.AddObject(ServiceContext.TimeoutManagerDataTableName, read);
}
else
{
context.Detach(read);
context.AttachTo(ServiceContext.TimeoutManagerDataTableName, read, "*");
context.UpdateObject(read);
}
context.SaveChangesWithRetries(SaveChangesOptions.ReplaceOnUpdate);
}
catch (DataServiceRequestException ex) // handle concurrency issues
{
var response = ex.Response.FirstOrDefault();
//Concurrency Exception - PreCondition Failed or Entity Already Exists
if (response != null && (response.StatusCode == 412 || response.StatusCode == 409))
{
return;
// I assume we can ignore this condition?
// Time between read and update is very small, meaning that another instance has sent
// the timeout messages that this node intended to send and if not we will resend
// anything after the other node's last read value anyway on next request.
}
throw;
}
}
bool TryGetLastSuccessfulRead(ServiceContext context, out TimeoutManagerDataEntity lastSuccessfulReadEntity)
{
var query = from m in context.TimeoutManagerData
where m.PartitionKey == GetUniqueEndpointName()
select m;
lastSuccessfulReadEntity = query
.AsTableServiceQuery(context)
.AsEnumerable() //TSQ does only follows continuation tokens for listings, not for single entity results, yet continuation tokes can still happen in this case
.SafeFirstOrDefault();
return lastSuccessfulReadEntity != null;
}
bool TryGetLastSuccessfulRead(ServiceContext context, out TimeoutManagerDataEntity lastSuccessfulReadEntity)
{
lastSuccessfulReadEntity = (from m in context.TimeoutManagerData
where m.PartitionKey == GetUniqueEndpointName()
select m).SafeFirstOrDefault();
return lastSuccessfulReadEntity != null;
}
